The official catalog of inspired writings, known as the Old and New Testament.

Before the close of the 4th century there was much uncertainty concerning this list of Divinely-inspired books, due to conflicting Jewish and Christian traditions. For the Old Testament the Jews distinguished the books contained in the Hebrew Bible (see Protocanonical) from the additional writings (see Deutebocanonical) preserved by the Jews of Alexandria in their venerated Greek version, the Septuagint. Early Christian writers bear witness to a widespread influence of this distinction within the Church, until official decrees established uniformity regarding the extent of the canon. The formation of the New Testament canon also shows a gradual development. The earliest collections of the Apostolic writings were made for the purpose of public reading in the churches (Colossians 4). However, since other edifying books were also so used by the first Christians, the special Divine character of some of the inspired writings was lost sight of in the approved reading-lists. Thus the Muratorian Canon (c.170 AD) mentions all the New Testament books, except Hebrews, James, and probably 1 and 2 Peter, but also includes, with reservations, the apocryphalApocalypse of Peter and the Shepherd of Hermas. Forgeries of heretics under the imputed authorship of one or the other of the Apostles, as well as erroneous interpolations into the sacred text, made the faithful suspicious and, as a result, doubt was for some time cast upon the following books and passages: Hebrews; James; Jude; 2 Peter; 2 and 3 John; Apocalypse; Mark, 16, 9-20; Luke, 22, 43-44; and John, 7, 53, to 8, 11. The oldest extant catalog which includes all the canonical books is that of Saint Athanasius (39th Festival Letter in 367).

The first official decision concerning the canon of the Holy Scriptures was given at a Roman synod under Pope Damasus in 382, approving without distinction the entire list of our present canon. In the same manner the Synod of Hippo in 392 and the Third Council of Carthage in 397 accepted the complete canon. In a letter to Exsuperius, Bishop of Toulouse, Pope Innocent I in 405 pronounced in favor of all the books. The question of a distinction was again discussed during the Council of Florence, whereupon Pope Eugene IV published a Bull, 1441, in which he attributed the inspiration of the same Holy Ghost to all the books received by the Church. With an appeal to these earlier voices, the Fathers of the Council of Trent in their famous decree of 8 April1546, definitely declared as “sacred and canonical” all the books of the Old and New Testament contained in the Vulgate, listing them as follows. Of the Old Testament: the five books of Moses; Josue; Judges; Ruth; four books of Kings; two of Paralipomenon; two of Esdras; Tobias; Judith; Esther; Job; the Psalter; Proverbs; Ecclesiastes; Canticle of Canticles; Wisdom; Ecclesiasticus; Isaias; Jeremias with Baruch; Ezechiel; Daniel; the 12 minor prophets; and two books of Machabees. Of the New Testament: the four Gospels; the Acts of the Apostles; 14 Epistles of the Apostle Paul; two Epistles of Peter the Apostle; three Epistles of John the Apostle; one of James the Apostle; one of Jude the Apostle; and the Apocalypse of John the Apostle. The Protestant reformers of the 16th century adhered to the narrower canon of the Hebrew Bible, and in the New Testament rejected Hebrews, James, Jude, and the Apocalypse. Modern Protestant Bibles, however, usually contain all the New Testament books.